The long-term goal of this project is to understand how the brain stabilizes memories after they have been retrieved. Using rats, this project will focus on the contribution of transcriptional and translational processes during the periods following retrieval of stored memory. The contribution of these processes will be elucidated using two main approaches. The first approach is to use targeted infusion of drugs that prevent either protein (translation) or mRNA (transcription) synthesis into brain regions known to be involved in fear conditioning. The second approach is to use antisense oligodeoxynucleotides (ODNs) to examine the role that specific proteins play in stabilizing memory after retrieval. These goals will be achieved with a series of experiments. In these experiments rats will be trained to fear a neutral conditional stimulus (CS) paired with an unconditional stimulus (UCS). A day later, animals will be "reminded" of this association with short presentations of CS, and drug infusions will immediately follow. Memory will be assessed the final day by longer exposures to the CS. These experiments will answer questions about which brain areas and molecular processes contribute to the stabilization of fear memory after retrieval and, in general, should reveal the physiological underpinnings of how memory changes after retrieval.